PC Vs PETG Comparing Performance Uses and Costs

Imagine needing lighter, shatter-resistant eyeglasses, food packaging that balances safety with transparency, or automotive parts requiring both impact resistance and heat tolerance. With countless material options available, selecting the right plastic can be overwhelming. Today we examine two popular plastic materials—polycarbonate (PC) and polyethylene terephthalate glycol (PETG)—to help guide your material selection process.

Polycarbonate (PC) is an amorphous thermoplastic often called the "superhero" of plastics due to its exceptional strength, toughness, and glass-like transparency. These properties make it ideal for applications requiring durability and optical clarity, from automotive headlight covers to safety goggles and bullet-resistant windows.

PETG , a copolymer thermoplastic, serves as a versatile "all-rounder." It combines the benefits of PET with glycol modification, offering excellent chemical resistance, impact strength, and processing flexibility. Its food-safe properties make it particularly valuable for packaging applications, including carbonated beverage bottles.

PC stands out for its remarkable mechanical properties. With a refractive index of 1.58, it outperforms acrylic (PMMA) in optical applications while allowing thinner lens designs. Although susceptible to scratching, this can be mitigated through hard coatings.

The material's molecular weight significantly impacts its performance. Higher molecular weight PC offers greater toughness—critical for aerospace applications—while lower molecular weight variants provide easier processing at reduced cost.

PC demonstrates excellent UV stability when properly formulated, making it suitable for outdoor applications like roofing materials. However, it remains vulnerable to degradation from oils, solvents, and organic acids, which can rapidly compromise its structural integrity.

PETG distinguishes itself through food-contact safety (BPA-free), excellent recyclability, and processing versatility. It accommodates various manufacturing methods including extrusion, injection molding, and blow molding. The material's clarity and gloss enhance product aesthetics while its chemical resistance ensures packaging integrity.

Both materials offer recycling potential, though implementation challenges remain. PC recycling requires rigorous sorting to maintain quality, while PETG's distinctive recycling symbol (♹) facilitates identification. Current recycling rates for both materials remain below optimal levels.

Cost structures differ significantly. PC typically costs $2.80/kg for virgin material, while PETG ranges from $1.10–$1.80/kg for molded pellets. Specialty applications like 3D printing filaments command higher prices ($20–55/kg for PETG).

PC Alternatives:

• Acrylic (PMMA): Superior scratch resistance but lower strength
• Polystyrene (PS): Cost-effective for non-critical transparent applications
• ABS: Suitable when reduced mechanical performance is acceptable

PETG Alternatives:

• BOPP/BOPE films for packaging applications
• PET/HDPE for blow-molded containers
• Polypropylene for food handling applications

PC excels in demanding applications requiring optical clarity, impact resistance, and thermal stability. PETG proves ideal for food-contact applications, general packaging, and situations requiring chemical resistance. Engineers must carefully evaluate mechanical requirements, environmental conditions, regulatory compliance, and cost constraints when selecting between these versatile thermoplastics.